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PRACTICE · MEMBERSIntermediate · Single correct

PRACTICE / Electrostatic potential energy

An energy budget can rule out a destination

A particle with charge +2e starts with kinetic energy 120 eV in a stationary electrostatic field. No other force does work.

What potential rise would reduce its kinetic energy to zero?

Organize the givens & assumptions
  • Charge: +2e
  • Initial kinetic energy: 120 eV

Use energy conservation in the nonrelativistic regime. This is the energetic turning condition; the geometry must also permit the trajectory to reach that equipotential.

  1. A−60 V-60\ \mathrm V
  2. B60 V60\ \mathrm V
  3. C120 V120\ \mathrm V
  4. D240 V240\ \mathrm V

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